1. Field of the Invention
This invention relates to an improved valve construction having multiple pistons and to a method of making such a valve construction.
2. Prior Art Statement
It is known to provide a valve construction having a housing means provided with a chamber and port means leading to the chamber and having an axially movable piston means disposed in the chamber to interconnect certain of the port means together in relation to the axial position of the piston means that is caused by a condition responsive device and a spring means operatively associated with the piston means, the piston means comprising a plate and a plurality of pistons disposed in spaced substantially parallel relation and being carried by the plate to be axially moved in unison in the chamber under the influence of the condition responsive device.
For example, see the following U.S. patent:
(1) U.S. Pat. No. 4,228,817--Weaver
The pistons of the valve construction of item (1) above are integral with the plate means that carries the same and therefore are not movable relative thereto.
It is also known to provide an annular groove in each piston of the above prior known valve construction to render each piston more flexible in order to tend to self-align the pistons in the valve construction.
For example, see the following item:
(2) Copending patent application Ser. No. 328,934, filed Dec. 9, 1981--Weaver, now U.S. Pat. No. 4,380,251.